From fecad5091f35425246316ab25c8a9f2aa44a7051 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 20 Jul 2018 12:18:11 -0700 Subject: [PATCH] rcutorture: Reduce priority of forward-progress testing On !SMP tests, the forward-progress kthread might prevent RCU's grace-period kthread from running, which would defeat RCU's forward-progress measures. On PREEMPT tests without RCU priority boosting, the forward-progress kthread might preempt a reader for an extended time period, which would also defeat RCU's forward-progress measures. This commit therefore reduced rcutorture's forward-progress kthread's priority in those cases. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 9622192ec5c9..ac487ea8d245 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1710,6 +1710,8 @@ static int rcu_torture_fwd_prog(void *args) static DEFINE_TORTURE_RANDOM(trs); VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); + if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) + set_user_nice(current, MAX_NICE); if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) { init_rcu_head_on_stack(&fcs.rh); cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);